Researchers Reveal Asymmetric Response of Soil CH4 Uptake Rate to Land Degradation and Restoration
2020-11-13
Methane (CH4), next to carbon dioxide, is the second most important anthropogenic greenhouse gas. The global atmospheric CH4 has reached new highs at 1869 ppb at the end of 2018. The upland soils can uptake the atmospheric CH4, making up 10% of the global CH4 sink. However, this biggest biological CH4 sink is very susceptible to human activities, especially to land use/land cover change.
Given that both land degradation and restoration happened worldwide, together with their vital roles in regulating greenhouse gases, especially the CH4 flux, it is imperative to synthesis the abundant research achievements to figure out the general pattern and underlying mechanism of the effects of land degradation and restoration on soil CH4 uptake globally.
Supervised by Prof. CHENG Xiaoli, WU Junjun, a research assistant of Wuhan Botanical Garden, conducted a meta-analysis with data of 228 observations from 83 individual studies to identify the general patterns of the effects of land degradation and restoration on soil CH4 uptake rate, as well as the driving factors.
The response of soil CH4 uptake to land degradation and restoration was asymmetric. The asymmetric response was mainly manifested in two aspects: First, the increased soil CH4 uptake rate in response to the land restoration was smaller compared to the decrease in CH4 uptake rate induced by the land degradation. Land restoration could hardly reverse the negative effect of land degradation on soil CH4 uptake rate. Second, the capacity of soil CH4 uptake decreased rapidly in response to land degradation, and it was not dependent on the time since land use change. In contrast, land restoration significantly increased the capacity of soil CH4 uptake. But the recovery of the capacity of soil CH4 uptake was slow and it would take several decades.
The response of soil CH4 uptake to land degradation and restoration was mainly regulated by changes in the soil microenvironment, and changes in the substrate had little effect on it.
Results provide a comprehensive assessment of the response of soil CH4 uptake capacity to land degradation and restoration, which is beneficial to the making of sustainable land management policy, and also can reduce the uncertainties in CH4 uptake in response to global land use change.
This research was financially supported by the National Natural Science Foundation of China and the "Strategic Priority Research Program B of the Chinese Academy of Sciences”. Results have been published in Global Change Biology Entitled “Asymmetric response of soil methane uptake rate to land degradation and restoration: Data synthesis”.
Asymmetric response of soil methane uptake rate to land degradation and restoration (Image by WU Junjun)
